Answers

2016-05-03T00:42:55+08:00
    P  is proportional  to  r l      /   P = price,  r = radius  &   l  =  length
        thus P  = k r l      /      first find the constant    k
                324 =  k 1/2 * 12
                  k   = 324/6  =  54
       then  substitute it into the new equation
              P  =     54 *2/3*10 =   360 dollars
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  • Brainly User
2016-05-03T17:57:53+08:00
Let:
Constant - k (Unit price per ft²)
P - price
r - radius
L - length

Variation equation:

P = k r L

Find the constant:
(Convert inch to ft. ⇒  6 inch = 0.5 ft)

$324 = k (0.5 ft) (12 ft)
$324 = k (6 ft²)
k = $324/6 ft²
k = $ 54/ft²

If length is 10 ft and radius is 8 inch:
(Convert 8 inch to ft = 2/3 ft)

Price = k r L
Price = ($ 54/ft²) (2/3 ft) (10 ft)
Price = ($54 / ft²) (20/3 ft²)
Price = $ 360

ANSWER:  $ 360
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